1. Field of Invention
The present invention relates to a printer driver, and more particularly to a method of printing print data that enables removing bands of white space, such as margins and empty lines formed at the top and bottom of each page, when printing print data.
2. Description of Related Art
When print data produced by an application program is printed, margins are commonly formed at the top and bottom of each page. In addition, when the text, images, or other content contained in the print data for a page occupy less than a full page, the content may be printed in a vertically-centered orientation, with a number of empty lines inserted at both the top and bottom of the page contiguous to the top and bottom margins. These bands of white space formed at the top and bottom of each page are inserted so that the text and images contained in the print data will be printed in the center of the page and positioned according to a specified format.
However, when print data is printed simply to verify the content of the text and images contained in the print data before printing the final printout in the desired output format, it is not necessary to include the bands of white space at the top and bottom of each printed page. Removing the data for the top and bottom bands of white space from the print data so that only the data contained in the text and images is printed would therefore be economical, because the amount of paper consumed for printing would be reduced.
Japanese Unexamined Patent Appl. Pub. JP-A-H06-83823 is directed to a data output device that can generate print data from which data for the bands of white space is removed from the print data. The device taught in JP-A-H06-83823 divides the print image of the print data into a plurality of lines, determines for each line whether the line is blank, and removes white space by removing the data for each line determined to be blank from the print data.
Japanese Unexamined Patent Appl. Pub. JP-A-H06-38001 is directed to a facsimile machine that can remove the data for bands of white space from image data received over a telephone line before printing the data. The facsimile machine taught in JP-A-H06-38001 divides the print image into a plurality of lines, determines for each line whether the line is blank, and removes white space by not sending the data for each line determined to be blank to the printing unit.
A problem with these methods of removing data for lines determined to be white space from the print data is that, in addition to removing bands of white space at the top and bottom of each page, they also remove bands of white space intentionally included in the content contained in the middle area to be printed between the white space at the top of the page and the white space at the bottom of the page. This changes the layout of the text and images in this middle area, making it no longer possible to confirm the placement of text and images in this middle area.
The foregoing related art does not consider whether the full printing width of the print head in the transportation direction of the recording medium is used when printing the bottom (trailing) end of the middle area of each page, or whether only part of the printing width of the print head is used. This means that in order to prevent the bottom of the middle area of a page (which is printed first) and the top of the middle area of the second page (which is printed next) from overlapping, the recording medium must be advanced at least the printing width of the print head after finishing printing the middle area of the first page, or printing the middle area of the second page must start after advancing the recording medium at least the printing width of the print head.
However, advancing the recording medium in this way produces bands of white space between the middle areas printed for each page, even though the data for the bands of white space at the top and bottom of each page has been removed from the print data.
FIG. 7 illustrates one aspect of the problem. The print head 101 (positioned at the side of the recording medium 100) is shown relative to the recording medium 100. More particularly, 101(1) depicts the position of the print head when the bottom end part of the middle area of the first page was printed, and 101(2) depicts the position of the print head after the recording medium 100 was advanced the printing width Q of the print head 101 after printing the middle area was finished. If only a portion (the shaded part) of the printing width Q of the print head 101 is used to print the bottom end part of the middle area of the first page and the recording medium 100 is then advanced only printing width Q, the print head 101(2) will not be positioned adjacent to the middle area of the first page and will instead be separated distance R from the position adjacent to the first printed middle area. This distance R is equal to the remaining portion of the printing width of the print head 101 that was not used for printing the bottom end of the first middle area. If printing the print data for the next page starts from this position, a band of white space will be formed between the bottom end of the first middle area and the top end of the middle area that is printed next.